• 한국수소및신에너지학회논문집
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• 제19권4호
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• pp.276-282
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• 2008

The effects of hydrogen enrichment to methane have been investigated with swirl-stabilized premixed hydrogen-enriched methane flame in a laboratory-scale pre-mixed combustor. The hydrogen-enriched methane fuel and air were mixed in a pre-mixer and introduced to the combustor through different degrees of swirl vanes. The flame characteristics were examined for different amount of hydrogen addition to the methane fuel and different swirl strengths. The hydrogen addition effects and swirl intensity on the combustion characteristics of pre-mixed methane flames were examined using micro-thermocouple, particle image velocity meter (PIV) and chemiluminescence techniques to provide information about flow field. The results show that the flame area increases at upstream of reaction zone because of increase in ignition energy from recirculation flow for increase in swirl intensity. The flame area is also increased at the downstream zone by recirculation flow because of increase in swirl intensity which results in higher centrifugal force. The higher combustibility of hydrogen makes reaction faster, raises the temperature of reaction zone and expands the reaction zone, consequently recirculation flow to reaction zone is reduced. The temperature of reaction zone increases with hydrogen addition even though the adiabatic flame temperature of the mixture gas decreases with increase in the amount of hydrogen addition in this experiment condition because the higher combustibility of hydrogen reduces the cooler recirculation flow to the reaction zone.

• 대한기계학회논문집B
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• 제36권1호
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• pp.75-81
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• 2012

고온의 동축류 공기와 수소가 함유된 메탄 연료제트에서 자발화된 층류 부상화염의 특성을 실험적으로 조사하였다. 그 결과로 순수 메탄 제트에서 자발화되는 경계 온도인 920 K 를 초과하는 초기 온도에서 메탄/수소 혼합기의 자발화된 부상화염은 연료 몰분율에 따라 삼지화염 또는 마일드 연소를 보였고, 제트속도에 따라 부상화염의 높이가 증가하는 전형적인 특성을 보였다. 소량의 수소가 첨가된 부상화염의 높이는 메탄의 경우와 유사하게 단열적 점화지연시간의 2 승에 대한 의존성이 유지되었다. 반면에, 초기 온도가 920 K 미만인 경우에서 화염은 수소의 점화 촉진에 의해서 자발화 되었다. 그리고 제트속도가 증가함에 따라 자발화된 부상화염의 높이는 비선형적으로 감소하는 독특한 특성을 보였으며, 수소의 선호확산이 그 현상에 대해서 중요한 역할을 할 것으로 예상된다.

• 한국연소학회지
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• 제17권3호
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• pp.1-8
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• 2012

The CO emission characteristics of interacting hydrogen and methane partially premixed flames were numerically investigated. A counterflow geometry was introduced to establish interacting two partially premixed flames. An one-dimensional OPPDIF code was used to simulate the interacting flames. The GRI-v3.0 was used to calculate the chemical reactions. Emission index for CO(EICO) was evaluated to quantify the CO emitted from the interacting flames. The global strain rate and equivalence ratios for each flame(${\Phi}_{CH_4}$ and ${\Phi}_{H_2}$) were used as parameters to control the extent of interaction between two partially premixed flames. When ${\Phi}_{CH_4}$ was kept to stoichiometric condition and ${\Phi}_{H_2}$ was at rich condition, unburned H2 species of hydrogen flame was transported to the methane flame and affected reactions related with CO formation. When ${\Phi}_{CH_4}$ increased from a stoichiometry to rich condition while ${\Phi}_{H_2}$ was kept to stoichiometric condition, EICO increased initially, had a peak value at ${\Phi}_{CH_4}=1.5$ and decreased gradually. This could be elucidated with an analysis for the elementary reactions related with CO formation.

• 한국추진공학회지
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• 제18권3호
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• pp.1-7
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• 2014

친환경 추진제인 액체메탄을 연료로 사용하는 이원추진제 로켓엔진의 이론성능분석을 통해 엔진의 설계변수를 도출하였다. 엔진의 연소성능 예측을 위해 CEA를 활용한 화학평형해석을 수행하였으며, 추진제 혼합비 및 연소실 내부압력에 따른 연소성능 특성을 고찰하였다. 엔진의 특성길이 도출을 위해 1차원 액적기화모델을 적용하여 성능변수 변화에 따른 추진제의 기화시간을 계산하였으며, 지상연소 이론성능분석을 통해 메탄 이원추진제 로켓엔진의 설계제원을 제시하였다.

• 한국수소및신에너지학회논문집
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• 제34권1호
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• pp.38-46
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• 2023

Carbon neutrality policies have been strengthened to reduce emissions, and the importance of technology road maps has been emphasized. In the global industrial boiler market, carbon neutrality is implemented through fuel diversification of methane-hydrogen mixture gas. However, various problems such as flashback and flame unstability arise. There is a limit to implementing the actual system as it remains in the early stage. Therefore, it is necessary to secure the source technology of methane-hydrogen hybrid combustion system applicable to industrial fields. In this study, control program for methane-hydrogen fuel conversion was developed to expect various parameters. After determining the hydrogen mixing ratio and the input air flow, the fuel conversion control algorithm was constructed to get the parameters that achieve the target oxygen concentration in the exhaust gas. LabVIEW program was used to derive correlations among hydrogen mixing rate, oxygen concentration in exhaust gas, input amount of air and heating value.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2014년도 제49회 KOSCO SYMPOSIUM 초록집
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• pp.141-142
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• 2014

This numerical study was carried out to optimize dual fuel combustion on natural gas-diesel in static chamber. Spray experiments conducted under conditions of premixed methan 0%, 5% and 10%. In the results, penetration decreases when premixed methane is increasing. Constants of numerical models were acquired from results of spray experiments to enhance accuracy of numerical study. And dual fuel engine simulation was implemented by using AVL-FIRE with acquired constants.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2004년도 제22회 춘계학술대회논문집
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• pp.99-105
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• 2004

The effects of pressure on combustion characteristics of the conical flameholder were investigated experimentally in the pressure range from 0.11 ㎫ to 0.40 ㎫. The result shows that the total equivalence ratio of lean limit becomes lower as the combustor inlet pressure rises and NOx emission is proportional to the pressure to the 0.5th power.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2015년도 제51회 KOSCO SYMPOSIUM 초록집
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• pp.139-141
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• 2015

• 한국토양비료학회지
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• 제48권6호
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• pp.697-704
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• 2015

This study was carried out to assess bioenergy conversion efficiency by biogas and solid fuel production in the cattle feedlot manure discharged from beef cattle barn. Feedlot manure was sampled from the cattle farmhouse located in Yong-in, Gyeonggi during the mid-fattening stage, periodically. The chemical characteristics, BMP (Biochemical methane potential) and HV (Heating values) of feedlot cattle manures were analyzed. Total solid contents of cattle feedlot manure were in the range of 29.98~44.28%, and volatile solid contents were in the range of 23.53~24.47%. In the anaerobic digestion of cattle feedlot manure, the methane production potential has increased from 0.141 to $0.187Nm^3kg^{-1}-VS_{added}$. The methane production of fresh cattle feedlot manure showed the range $0.141{\sim}0.187Nm^3kg^{-1}$-Manure (average $0.047Nm^3kg^{-1}$-Manure), the LHVs (lower heating values) of the produced methane were in the range of $316{\sim}560kcalkg^{-1}$-Manure (average $400kcalkg^{-1}$-Manure). In the direct combustion of fresh cattle feedlot manure, the LHVs were measured in the range of $747{\sim}1,271kcalkg^{-1}$-Manure (average $916kcalkg^{-1}$-Manure), and LHVs of solid fuel which have the water content of 20% were in the range of $2,694{\sim}2,876kcalkg^{-1}$-Manure (average $2,791kcalkg^{-1}$-Manure). Then, the drying energy of average $443kcalkg^{-1}$-Manure was consumed in the production of solid fuel which has a water content of 20%. Therefore, the direct combustion of cattle feedlot manure showed about 2.3 times higher LHV than the LHV of methane produced by anaerobic digestion. And LHV of solid fuel was about 6.0 times higher than the LHV of methane produced by anaerobic digestion. Then, the production of solid fuel presented more bioenergy conversion efficiency than the biogas production in the bioenergy use of cattle feedlot manure.

• 한국화재소방학회논문지
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• 제33권1호
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• pp.23-29
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• 2019

리튬이온 배터리와 같은 충전식 배터리는 에너지의 저장장치로서 최근의 에너지 이용의 변화에 따라 크게 주목받고 있을 뿐 아니라 실제로 다양한 소형 전기기기 및 전기 자동차의 전기에너지 저장시스템으로 폭넓게 적용되고 있다. 하지만 리튬이온 배터리는 화재나 폭발 등의 위험성이 항상 존재하여 사용의 폭을 제한시키고 있다. 배터리화재가 일반적인 화재와의 다른 특성은 여러 가지가 있지만 그 중에 가연물질이 전해질에서 이온화 되어있다는 특성이다. 본 연구에서는 배터리 화재를 이해하기 위해서 양이온과 전자 등으로 이온화된 메탄 제트화염에서의 연소특성을 실험적으로 관찰하였다. 화염 형상 및 화염안전성은 현재의 실험조건에서는 연료 이온화 효과가 없었고, 제트화염 후류에서 측정한 CO와 NOx의 농도가 이온화연료에서 모두 감소하는 것을 확인할 수 있었다. 또한 이온화 메탄 연소특성의 파라미터 연구를 위하여 수치해석의 반응기구를 수소첨가의 형태로 단순화하여 이온화연료의 연소특성을 모사할 수 있는지에 대한 모델링 검토를 수행하였다. 연료 이온화의 영향으로 수소의 농도는 증가시키되 반응 후 온도는 일정함을 가정하여 모델링하면 실험결과와 일치하는 결과를 얻을 수 있었다.